1. Field of the Invention
The present invention relates to resolver-malfunction-detection methods that are most suitable for electromotive power steering systems for vehicles, etc., and to systems for controlling motors using the methods.
2. Description of the Related Art
FIG. 7 is a view illustrating a conventional resolver-signal-detection system (refer to Japanese Laid-Open Utility Model Publication 99,815/1987).
In FIG. 7, numerals 51a and 51b denote square circuits, numerals 52a and 52b denote rectifier circuits, numeral 53 denotes an adder circuit, numeral 54 denotes a voltage regulator circuit, and numeral 55 denotes a comparator circuit.
A method is disclosed, in which, by comparing the sum of the square of a sine signal and the square of a cosine signal with a predetermined voltage, so that an abnormality is determined.